Hydraulic pump and motor



May 2, 1933.

G. cuT'rAT HYDRAULIC run? AND moToR Filed July 15', 1928 5 Sheets-Sheet 1 May 2,1933. I cu -r: I 1,906,787 HYDRAULIC PUMP AND MOTOR;

Filed July 17. 1928 5 Sheets-Shet 2 May 2, 1933. G. CUTTAT 1,905,787

HYDRAULIC PUMP AND MOTOR' Filed July 17, 19:58 1 5 Sheets-Sheet 3' Fig.3.

. reaction.

Patented May 2, 1933 UNITED STATES PATENT OFFICE GEORGES CUT'IAT, OI PABIQIBANCE, ASSIGNOR TO SOCIETE ANONYME DES ETABLISSE- mEN'rs GUTTAT, or rams, FRANCE HYDRAULIC PUMP AND MOTOR 7 Application filedluly 17, 1928, Serial No. 298,407, and in France April 18, 1928.

The present invention has for object a to each-other-the ressure and the outflow for aconstant driving torque applied to the driving shaft.

2. It comprises a device for guiding the pistons in their cylinders, specially devised in view of diminishing, in a large proportion, thereaction of the first ones on the second ones and, consequently, 'of reduclng the friction and wear resulting from this This guide device can moreover be applied to any motor or pump in which the reciprocating movement of the pistons is effected by means other than, an eccentric. In accordance-with the invention, in the systems of pumps or motors of the type under consideration: a

(a) The variation of the cylinder charge is determined by variation of the length of the stroke of the pistons in the respective cylinders. This variation is obtained by the combination of two eccentrics, vizz a first eccentric carried by the fixed shaft and a second eccentric movable and adjustable on the first one by means of a manual control or by an auxiliary motor. These two eccentrics are so devised that, from a position correspondingto the maximum eccentricity, one-half revolution of the eccentric 'movable on the fixed eccentric, brings back this eccentration to zero, by passing through all the intermediate values;

(b) The distribution is ensured by a rotating distributing member accompanying continuity of the distributionas, during this displacement, the point of eccentricity, by

varying from its maximum position to its .mlnimum poc'lion (or vice versa) moves.

according to a spiral curve and not rectilinv eccentric. 1. It allows of vary1ng-in reverse ratio early according to the axis of the fixed shaft.

,In 'these conditions, the dead centers which correspond to the moments of change of direction of the distribution-move by accompanying the movement'of the movable cerned, the system in accordance with the invention advantageously differentiates from other known systems having also an adjustment of the eccentration by rotationbut in which the distributor is not displaced In these known systems, the adjustment of the distribution is destroyed everytime the eccentricity is varied, so that the operation guide link holding the corresponding link in a position approximately parallel to the radius'starting from thecenter of the driv ing shaft/and passing through the axis of the corresponding piston; for that purpose,

each small link is pivoted on the frame of the pistons by its end opposite to. that which receives the link.

((5) For a form of construction which will be more particularl centric is in the shape 0 a circular raceway in which the small links fit at their respective pivoting points. '4

At these points, rollers rigid with the small link constantl follow the raceway,

' so" that the control 0 each of the pistons is positive, as well during the suction cycle as during the compression cycle; the raceway is mounted on the eccentric through the medium of ball or roller bearings or equivalent systems.

The shape of the raceway may be varied ;As far as this. point is conat the same time as the adjustable eccentric.

described, the ecindicate how the invention can be carried into practice.

In the drawings:

Fig. 1 is a partial axial section of a pump (having five rotary cylinders) combining the devices forming the subject matter of the present invention (adjustment of the eccentricity, rotating distributor, guiding of the pistons).

Fig. 2 is an end view and partial section, on the side where takes place the control of the variation of the cylinder charge.

Fig. 3 is a half cross section, on the left hand side, made through the plane common to the axes seen through the axis of the cylinders and pistons and a half section, on the right hand side, made through the driving finger of the movable eccentric.

Fig. 4 is a. detail view of the system of link and small guide links which characterizes the invention.

Fig. 5 shows another form of construction of this guide system.

Fig. 6 is a cross section of a modification in which the guide system is applied to a pump or motor having fixed cyhnders and a simple non-adjustable eccentric.

Fig. 7 is a partial axial section corresponding to Fig. 6.

Fig. 8 illustrates a constructional modi- I fication in whlch several groups are mounted in parallel according to a known method.

In Figs. 1 to 3, 1 designates a shaft adapt-- ed to actuate the pump; this shaft can rotate when suitable power is applied thereto.

When the device operates, on the contrary, as a motor,-the shaft ltransmits the power supplied by the device to any other device to be actuated. v

2 designates a plate angularly rigid with the shaft 1 and concentric with the latter.-

3 designates .a bearing constituted, in the example illustrated, by a ball bearing; 4 is a cheek supporting this bearing.

5 designates the body of the cylinders angularly rigid with the plate 2' and, consequently, withv the shaft 1.

6 is a fixed shaft coaxial with the shaft 1..

7 is'a first eccentric rigid with this shaft 6. 8 is a bearing constituted, in the example illustrated, by a .ball bearing; this hearing allows the free rotation of the structure movable on the eccentric 7 and, consequently,

check 4: and 23 is a the rotation of .1, 2 and 5 about the fixed shaft 6. v

9 is another bearing, similar to the bearing 8 and fulfilling the same function.

10 is a'second eccentric movable about the eccentric 7 so as to cause the resulting ec- 4 rotate on the eccentric '10.

13, 13=13 are the rollers of a guide sys- "tem which will be described later on (Figs.

4 and 5) these rollers guided by the raceway 12 are rigid with small links shown at 14,

These rollers can be replaced by ball or roller hearings or by shoes according to the mode of application and without departing from the scope of the invention.

15, 15"-15 are the links of the pistons 16 to 16 movable respectively in'cylinders l7 Each of these cylinders is closed by a plug 18 forming a head for the piston 17.

19 designates one of the pipe lines causing the cylinders to communicate with the distributor.

20 (Fig. 1) is a plug; 21 is one-of the needle screws or blow-through. devices (to which access may be had by unscrewing the plug 20); these blow-through devices allow the evacuation of the air when putting the system in service.

22 is a casing to which is secured the cheek secured to the easing 22. I

25 and 26 are obturating washersadapted to avoid leakage.

27 designates the distributor about which rotates the body 5 of the cylinders.

28 is a first annular chamber forming'a delivery chamber when the device operates as a pump, and an exhaust chamber when the device operates as a motor.

29 is a second annular chamber corresponding to the suction in the case of operation as a pump, and to the admission in the case of operation as a motor.

. 30 1s a p1pel1ne communicating with the chamber 28; 31 is a second pipe line communicating with the chamber 29.

32 is a key securing the distributor on a tubular shaft 33, which can rotate on the shaft 33 is. actuated.

36 is a worm wheel angularly rigid with the tubular shaft 33.

37 is a system for securing the wheel 36 on the shaft 33.

38 is a casing forming a, cheek and secured on the cheek 23.

39 is a cheek secured on this casing 38.

40 is a key renderingthe shaft 6 angular-1y rigid with the fixed cheeks 39, 38, 23, 22 and 4 this key prevents any rotary movement of the shaft i 41 is a nut with a lock-nut securing the shaft 6.

' 42 is a cup leather adapted to avoid leakage of liquid outside the chamber 29.

43 is worm gearing with the toothed wheel'36 and opera ted by a hand-wheel 44.

This driving system can be replaced, without departing from the scope of the i'nvention, by any other suitable system, such as a lever for instance.

The wheel 36 can also be driven by means of an auxiliary motor, thus ensuring the automaticity of this drive, if necessary, th s auxiliary motor being then driven by means of manoinetric or dynalnometric relays orby any-other suitable member.

The operation of the device used as a pump will now be described:

If the shaft 1 is caused to rotate by a suitable power, it drives inits movement the plate 2 which in its turn drives the body 5 of the cylinders 17; consequently the cylinders take a movement of rotation about the fixed shaft 6.

It will first be assumed that the relative arrangement of the eccentrics and 7 corresponds to the maximum 'eccentration which can be obtained (as it has been assumed in the drawings); in this case, the pistons 16 to 16, radially urged by the eccentric and guided for instance by a device similar to that which will be described later on, effect upon each revolution, in their respective cylinders, a compression stroke and a suction stroke; the common length of these two strokes is-a function of the resulting eccentricity between 7 and 10.

f it is now assumed that, by acting on the hand wheel 44 which drives the worm 43 and the wheel 36, the tubular shaft 33 is caused to rotate, the eccentric 10 will be driven in this movement of rotation, owing to the action of the finger 34 on the notch 35 formed in the eccentric 10; considering this latter is also out of center on the eccen trio 7, when one half revolution will thus have been effected,the generating line situated atsthe maximum oint of eccentration of 10 will coincide with the generating line situated at the minimum point of eccentricity of 7. At this moment, the eccentric '10 will be coaxial with the shafts 1 and 6. The pistons will no longer be subjected to any radial displacement and, consequently, the, outflow of. the pump will be reduced to zero.

It will be easily understood that between these two extreme relatiyepositions of the eccentrics 7 and 10, it will be possible to adopt any of the intermediate positions; thus, the outflow can pass, in an absolutely progressive manner,- from zero to its maxi-- mum value.

It will alsobe understood that the more the value of the effective eccentricity is diin the same proportions.

. It will therefore be seen that it is possi- I ble, whilst applying to the driving shaft 1' r a constant torque, to obtain a variable pressure and outflow,- functions reverse from each other, this variation being obtained in a very simple manner by acting on the hand wheel 44. V v

In the case of operation as a motor, for a constant pressure supplied to the inlet chamber 29, it is possible to obtain a'range of progressive speeds 'from a minimum speed corresponding to the maximum eccentration, to a maximum speed corresponding to the point for which the eccentration is minimum. e e

It is necessary to insist on .the fact that the distributor 27 is secured on the tubular shaft 33 and that it moves with the latter when a modification of the value of eccentration is effected; it has been explained in the preamble that it is necessary that these parts should be rigid together as, upon operation of the eccentric, the dead centers of the system move according to an extent equal to the angular displacement of the eccentric, the movement being circular. The appli-J cant is aware that the mode of operatlon .which has just. been described, is known in its general lines and that it is applied to I hydraulic'pumps and motors.

However, in the deviceforming the subject-matter. of the present invention, the character of novelty resides not only in the fact that the eccentric members do not rotate, and that, by this very fact, the balancing of the system is perfectly ensured, but moreover, and particularly, in the fact that for each position of the movable eccentric, the distribution remains automatically regulated.

Ithas been seen that in this device ,the ec-' centricity is ensured by rotation'of a cylindrical member on another cylindrical member; considering all the points of the periphery of these two members remainin contact, a rational distribution of the stresses transmitted is constantly ensured.

In theexample described it has been assumed that the eccentricity can vary from zero to a maximum..

Likewise, -by devising the eccentrics in such a manner that one of them has ,a value of eccentricity greater than thatof the other,

iso

it will be possible to obtain by one half-revolution of the movable eccentric and by start-.

- reversal of the direction of circulation of which is itself a function, on the one hand,

the fluid in the pipe lines leading tothe apparatus.

We shall now describe the guide system for the pistons.

It is to be noted that if the pistons simply rested on the raceway and were provided with rollers in the said'raceway, they would be subjected to a reciprocating movement the extent of which would be equal to the amplitude of the movement of translation imposed by the eccentric 10.

However, during their stroke, these pis tons would be moreover sub]ected to a force of the amplitude of this movement and on the other hand, of the pressure of the fluid delivered; it will thus be understood that the wear of the cylindrical bodies and of the pistons would be rapid. This wear might be attenuated byproviding these pistons with "links directly engaged by a crown replacing the raceway 12; for avoiding the reversal of the links, one of them should then be directly connected to this crown; this device is known and commonly applied.

Notwithstanding these arrangements, the links would take back, in the greater portion of their stroke, an oblique position relatively to the axis of the pistons; the force urging these pistons being at right angles to their axis, both forces will have a resultant which will still tend to apply the piston against the Wall of the cylinder according to one of their generating lines, so that the wear of the cylinders will still be very rapid; for practically attenuating this wear, it will be necessary to diminish the value of the above mentioned resultant and, for that purpose, to diminish the value of the maximum angle formed by the axis of the lin k during its displacement, relatively to the axis of the piston. i

, tively long links, which would determine an increase of the cumbersomeness and of the weight. These two solutions-are known and currently applied, they have been recalled here only for comparison in order that the .advantageous features-of the present inventionmay more clearly appear. The said invention suppresses in factthe prejudicious effects mentioned, and this by the following arrangement (see particularly Figs. 4 and 5 One would thus be led to provide rela guided by the rollers 13. Each of the axes r of these rollers or of any other suitable equiv:

by means of aspherical member R secured by the members 48 and 49 and the screws 50 51.

The link 15 is itself connected to the piston 6 by means of a second spherical member R held in its housing, for instance by means of .a screw 56. Without departing from the scope of the invention, the ball joints R and R might quite as well be replaced by axes and rings, or by any other device fulfilling the same function. It will be understood that the oscillating movement of each of the links will be very' small; it will have for amplitude one half the pitch of an arc the chord of which will be a function of the piston stroke and of the radius described by the small link 14, which radius is itself function of the distance between the axis 47 and the fulcrum of the rollers on the raceway.

By way of example, if one considers a piston stroke of 20 millimeters and a link of 40 millimeters in length, with various known systems of assemblage which have been recalled above, the maximum angle, previously mentioned, is equal to 12.

If, on the contrary, the device in accordance with the invention is used, by maintaining the same values for the piston stroke and the length of the links, and if use is made of a. small link having 90 millimeters between axes (between rollers and pivoting points), the maximum value of the said latter are reduced inthe same proportions.

These data show the considerable practical advantage of the device illustrated.

Fig. 5 shows, by way of example, another formofconstruction of the small links. In this modification, each small link 14 pivots within a ring 52 maintained in the body 5. Its opposite end is tubular and the spherical member R is held in place by the screw 5 5.

Figs. 6 and 7 illustrate the application of this guide system to a having fixed cylinders.

pump (or motor) In these figures: I a I 61 is a shaft adapted to receive the energy 7 for actuating the pump;

62 is an eccentric rigid with this shaft;

63 is a double circular raceway centered on the eccentric 62; y

64 and 65 are ball or roller bearings allowing the rotation of the eccentric 62 within the raceway 63.

As previously tively pivoted by axes 47 to 47 on the fixed frame 75 of the cylinders;

13 to 13 are rollers respectively rigid :with these small links 15 to 15 are the links connecting the pistons 1.6 to 16 to the small links;

In the same figures: 72 to 72 are plugs forming 7 cylinder heads;

73 is one of the pipe lines feeding the cylinders; p

74 designates one of the blow-through devices adapted to evacuate the air atcthe time the apparatus is put in action. 7

'75 's the frame in which are bored the cylinders and channels. i

7.6 is a cheek of this frame, forming a i bearing;

= 77 is another cheek acting as an obturator for the distributor;

78 is the body of the distributor; the latter is driven in rotation by the shaftGI, by means of the square part 79 on which it is freely mounted in the longitudinal direction. This square member can also be in the shape of an Oldham joint or of any other similar driving device;

8( ),is the delivery orifice and 81* the suction orifice of the apparatus; r 82 is a spring ensuring fluid-tightness be.- tween the rotary distributor and the frame:

83 is an'intermediate washeradaptedto facilitate the rotation of the distributor 78 at its points of contact with theframe 75;

84 isa cup leather adapted to ensurethe fluid-tightness ofthe distributor;

' device para lel; in this figure have been shown ree cylinders 17, 17 17" o crating in parallel; 1

forth in the foregoing description and in the following claim.

\ I claim In a system of hydraulic pumps motors or similar apparatus, multiple radial cylinders of the type in which the stroke of the pistons is controlled by an eccentric, this system comprising a rotating annular body wherein radial cylinders are hollowed out,

which communicate with the inner periphery of the annular body and include pistons having rods, "guiding links connected to the iston rods and connected to .the rotating ody, a device comprising a circular eccentric for drivin the said pistons, a raceway carried by said eccentric and consisting of two rings spaced apart, spherical members a for connecting the piston rods to the pistons, other spherical membersfor connecting the piston rods to the guiding links, rollers carried by each of the said guiding links and engagmg in the circular channel formed by the rings constituting the racewa The foregoing specification 0 my imrovements in hydraulic pumps and motors having radial fixed or rotary cylinders 6th day of J uly 1928.

signed by me this GEORGES CUTTAT.

the outflow of a cy inder 186111181 to ai value D, the total outflow of the group is equal to' 3D.. This mode-of groupin is moreover known and it is mentioned here onlyby way of example of application of the Invention. Likewise, the number of cylinders of one and the same cup and the arrangement of these cylin ers may vary.

. It is to be understood that various accessory modifications can be madefin the devices described by way of example. All the -modifications thus obtained are included within the scope of the invention if they apply the principle of the same such as set 

